Rotation of real spherical harmonics

Formulae for the rotation of real spherical harmonic functions are presented. To facilitate their application, values of the matrices d_m′m^(l)(π/2), which occur in the equations, are tabulated for 1 ≤ l ≤ 8 and 0 ≤ m′, m ≤ l. The application of the equations to spherical harmonic functions with normalization commonly used in charge-density analysis is described.